Hi Andy, > I've placed the test description and results of some SDR-IQ linearity > tests (in .PDF format) on my website given below. Look in the SDR > projects section. > > www.scrbg.org/g4jnt/SDRProjects.htm > > If one thing comes out of this test - it shows that the concept of > using Third Order Intercept Point (TOIP) as a measure of performance > for wideband digital receivers would appear to be completely flawed. > > For example, adding in a third tone F3, at a lower level while > monitoring the 2.F1 - F2 Intermod product, causes that product to drop > in amplitude dramatically. And why does the IMP stay reasonably > constant (in level, not dBc) as the input level of the two tones is > changed. > > Explanations please !
Have a look here: http://www.sm5bsz.com/digdynam/practical.htm The full text is in an article in QEX Nov/Dec 2006. 73 Leif / SM5BSZ
